Originally Posted by
bent-not-broken
If you've ever blown up a tube looking for a leak you know how much a tube expands. If you can get a tube into a tire it will work. Look at the rbig ange of sizes listed on the box of many tubes. Don't sweat it.
Yes, but as it expands the walls get thinner making it easier to puncture. A few mm isn't going to make much of a difference but I wouldn't a skinny tube designed for 23 to 25 mm tires inside a 45 mm tire for much longer than it took to get home.